A Robotic Sample Preparation Scheme for the High Performance Liquid Chromatographic Determination of Ivermectin in Animal Plasma

A lengthy sample preparation scheme for the high performance liquid chromatographic determination of the antiparasitic agent ivermectin at ppb concentrations in animal plasma is adapted to a laboratory robotic system. Sample treatment involves both liquid-liquid partitioning and solid phase extraction. Specific modifications to the manual procedure include the use of serial vortex mixings in place of batchwise lateral shaking and the substitution of small (6 mL), disposable solid phase extraction columns driven by compressed gas for large (25 mL), gravity-fed, reusable glass columns. Coupling these columns to an automated solvent dispensing device simplifies handling of the large solvent volumes prescribed in the manual procedure. A productivity gain over the manual procedure is realized when operating the robotic system in the single sample mode, and an additional gain is achieved by integrating the system for multiple sample handling. Equivalence to the manual procedure is demonstrated.